At present, many types of golf balls are commercially available in the world, but those used for tournaments or competitions officially authorized are generally two piece solid golf balls and thread wound golf balls,
The two piece solid golf balls are mainly approved by amateur golfers, because they are better in flight performance, durability and cut resistance than the thread wound golf balls. The two piece solid golf balls, however, have defects in shot feel, when hitting, and controllability in comparison with the thread wound golf balls.
Accordingly, there have been many proposals for improving the shot feel or controllability of the two piece solid golf balls, for example Japanese Patent Kokai Publication Hei 6 (1994)-142228 and the like. In order to let shot feel and controllability approach to those of the thread wound golf balls, the proposed solid golf balls adopt a three piece construction having two cover layers, of which an inner cover layer is formed from various cover material. The proposals, however, adversely affect on flight performance or keep it at the level of the conventional two piece solid golf balls. It is still desired to improve all of shot feel, controllability and flight performance.
Japanese Patent Kokai Publication Hei 2 (1990)-88087 proposes that n outer cover is formed from an ionomer resin neutralized with both sodium ion and copper ion, so-called dual ion ionomer resin. However, the dual ion ionomer resin is slightly colored with blue and green because of the presence of copper ion and therefore is not good for the outer cover, because it gives rise to defect in appearance.